Store more information in the kernel socket table.

Store enough information in the kernel socket table to distinguish
between different types of sockets. Previously we were only storing
the socket family, but this isn't enough to classify sockets. For
example, TCPv4 and UDPv4 sockets are both AF_INET, and ICMP sockets
are SOCK_DGRAM sockets with a particular protocol.

Instead of creating more sub-tables, flatten the socket table and
provide a filtering mechanism based on the socket entry.

Also generate and store a socket entry index ("sl" in linux) which
allows us to output entries in a stable order from procfs.

PiperOrigin-RevId: 252495895

2 files changed, 11 insertions, 4 deletions

diff --git a/pkg/sentry/socket/epsocket/epsocket.go b/pkg/sentry/socket/epsocket/epsocket.go
index e1e29de35..f67451179 100644
--- a/pkg/sentry/socket/epsocket/epsocket.go
+++ b/pkg/sentry/socket/epsocket/epsocket.go
@@ -228,6 +228,7 @@ type SocketOperations struct {
 	family   int
 	Endpoint tcpip.Endpoint
 	skType   linux.SockType
+	protocol int
 
 	// readMu protects access to the below fields.
 	readMu sync.Mutex `state:"nosave"`
@@ -252,7 +253,7 @@ type SocketOperations struct {
 }
 
 // New creates a new endpoint socket.
-func New(t *kernel.Task, family int, skType linux.SockType, queue *waiter.Queue, endpoint tcpip.Endpoint) (*fs.File, *syserr.Error) {
+func New(t *kernel.Task, family int, skType linux.SockType, protocol int, queue *waiter.Queue, endpoint tcpip.Endpoint) (*fs.File, *syserr.Error) {
 	if skType == linux.SOCK_STREAM {
 		if err := endpoint.SetSockOpt(tcpip.DelayOption(1)); err != nil {
 			return nil, syserr.TranslateNetstackError(err)
@@ -266,6 +267,7 @@ func New(t *kernel.Task, family int, skType linux.SockType, queue *waiter.Queue,
 		family:   family,
 		Endpoint: endpoint,
 		skType:   skType,
+		protocol: protocol,
 	}), nil
 }
 
@@ -550,7 +552,7 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int,
 		}
 	}
 
-	ns, err := New(t, s.family, s.skType, wq, ep)
+	ns, err := New(t, s.family, s.skType, s.protocol, wq, ep)
 	if err != nil {
 		return 0, nil, 0, err
 	}
@@ -578,7 +580,7 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int,
 	}
 	fd, e := t.FDMap().NewFDFrom(0, ns, fdFlags, t.ThreadGroup().Limits())
 
-	t.Kernel().RecordSocket(ns, s.family)
+	t.Kernel().RecordSocket(ns)
 
 	return fd, addr, addrLen, syserr.FromError(e)
 }
@@ -2324,3 +2326,8 @@ func (s *SocketOperations) State() uint32 {
 	// TODO(b/112063468): Export states for UDP, ICMP, and raw sockets.
 	return 0
 }
+
+// Type implements socket.Socket.Type.
+func (s *SocketOperations) Type() (family int, skType linux.SockType, protocol int) {
+	return s.family, s.skType, s.protocol
+}
diff --git a/pkg/sentry/socket/epsocket/provider.go b/pkg/sentry/socket/epsocket/provider.go
index e48a106ea..516582828 100644
--- a/pkg/sentry/socket/epsocket/provider.go
+++ b/pkg/sentry/socket/epsocket/provider.go
@@ -111,7 +111,7 @@ func (p *provider) Socket(t *kernel.Task, stype linux.SockType, protocol int) (*
 		return nil, syserr.TranslateNetstackError(e)
 	}
 
-	return New(t, p.family, stype, wq, ep)
+	return New(t, p.family, stype, protocol, wq, ep)
 }
 
 // Pair just returns nil sockets (not supported).